Impedance Magnitude Difference Answered

Hi there,

I am simulating a piezoelectric disc made from Ferroperm PZ26. I have measured the impedance magnitude of 5 of these PZ26 discs using an impedance analyzer and I am trying to get the simulated impedance magnitude to match closely to this measured impedance. I am using the radial mode of the disc and therefore looking at frequencies around 100 kHz. 

The problem I am having is that the experimental measurement has a much greater impedance magnitude than the simulated impedance. I have attached a plot which shows this.

I believe it could be something to do with the Q factor used when defining the PZ26 material. However, I have tried increasing the Q factor and, while the impedance magnitude does increase a little, there is still a very big difference in the impedance magnitude. 

I am hoping someone will be able to advise me on what steps I can take to try and correct this problem?

Thanks for your time,

Laura 

2 comments

  • Official comment

    Hi Laura,

     

    The amplitude difference is likely due to incorrect material properties. Since it is an amplitude difference it is likely that dielectric properties for the piezo in the simulation doesn't match your experiment. I would recommend sweeping the piezo dielectric properties by 10% to see if one of these gives you a closer match.

    Best Regards,

    Chloe

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  • I went through a similar exercise recently on a piezo disk of 30 kHz resonance frequency.  I only had one sample, so no way to back out possible manufacturing tolerances. You have 5 samples so can get a better look at that. The one thing I learned from this exercise with OnScale was I had to lower "freqint" from its default settings in the examples, to 100 kHz, to get a halfway sensible fit.

     

     

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